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Abstract:

An antenna configured in a hybrid circuit provides a compact design for a
hearing aid to communicate wirelessly with a system external to the
hearing aid. In an embodiment, an antenna includes metallic traces in a
hybrid circuit that is configured for use in a hearing aid. The antenna
includes contacts in the hybrid circuit to couple the metallic traces to
electronic devices in the hybrid circuit. In an embodiment, the metallic
traces form a planar coil design having a number of turns of the coil in
a substrate in the hybrid circuit. In another embodiment, the metallic
traces are included in a flex circuit on a substrate in the hybrid
circuit. An antenna configured in a hybrid circuit allows for use in a
completely-in-the-canal hearing aid.

Claims:

1. An apparatus for use in a hearing aid, comprising: communication
electronics adapted for use with a hybrid circuit in the hearing aid; and
an antenna including one or more metallic traces connected to the
communication electronics, the antenna adapted for assembly with the
hybrid circuit.

Description:

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation of U.S. application Ser. No.
12/550,821, filed Aug. 31, 2009, which is a continuation of U.S.
application Ser. No. 11/357,751, filed on Feb. 17, 2006, now issued as
U.S. Pat. No. 7,593,538, which is a continuation of U.S. application Ser.
No. 11/287,892, filed on Nov. 28, 2005, which is a continuation of U.S.
application Ser. No. 11/091,748, filed on Mar. 28, 2005, which
applications are incorporated herein by reference in their entirety.

FIELD OF THE INVENTION

[0002] This invention relates generally to antennas, more particularly to
antennas for hearing aids.

BACKGROUND

[0003] Hearing aids can provide adjustable operational modes or
characteristics that improve the performance of the hearing aid for a
specific person or in a specific environment. Some of the operational
characteristics are volume control, tone control, and selective signal
input. These and other operational characteristics can be programmed into
a hearing aid. A programmable hearing aid can be programmed through
connections to the hearing aid and by wirelessly communicating with the
hearing aid.

[0004] Generally, hearing aids are small and require extensive design to
fit all the necessary electronic components into the hearing aid or
attached to the hearing aid as is the case for an antenna for wireless
communication with the hearing aid. The complexity of the design depends
on the size and type of hearing aids. For completely-in-the-canal (CIC)
hearing aids, the complexity can be more extensive than for in-the-ear
(ITE) hearing aids or behind-the-ear (BTE) hearing aids due to the
compact size required to fit completely in the ear canal of an
individual.

SUMMARY OF THE INVENTION

[0005] Upon reading and understanding the present disclosure it is
recognized that embodiments of the inventive subject matter described
herein satisfy the foregoing needs in the art and several other needs in
the art not expressly noted herein. The following summary is provided to
give the reader a brief summary that is not intended to be exhaustive or
limiting and the scope of the invention is provided by the attached
claims and the equivalents thereof.

[0006] In an embodiment, an antenna includes metallic traces in a hybrid
circuit that is configured for use in a hearing aid. The antenna includes
contacts to connect the metallic traces to electronic circuitry of the
hearing aid. In an embodiment, the metallic traces form a planar coil
design having a number of turns of the coil in a substrate in the hybrid
circuit. In another embodiment, the metallic traces are included in a
flex circuit on a substrate in the hybrid circuit.

[0007] These and other embodiments, aspects, advantages, and features of
the present invention will be set forth in part in the description which
follows, and in part will become apparent to those skilled in the art by
reference to the following description of the invention and referenced
drawings or by practice of the invention. The aspects, advantages, and
features of the invention are realized and attained by means of the
instrumentalities, procedures, and combinations particularly pointed out
in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] A more complete understanding of the invention and its various
features may be obtained from a consideration of the following detailed
description, the appended claims, and the attached drawings.

[0009] FIG. 1 depicts an embodiment of a hearing aid having an antenna for
wireless communication with a device exterior to the hearing aid, in
accordance with the teachings of the present invention.

[0010] FIGS. 2A-2B show overviews of embodiments of an antenna in a
substrate for inclusion in a hybrid circuit configured for use in a
hearing aid, in accordance with the teachings of the present invention.

[0011] FIG. 3A depicts an embodiment of a hybrid circuit configured for
use in a hearing aid including a substrate containing a planar antenna,
in accordance with the teachings of the present invention.

[0012] FIG. 3B depicts an expanded view of the embodiment of layers of a
hybrid circuit configured for use in a hearing aid shown in FIG. 3A
illustrating the planar antenna in a substrate in the hybrid circuit, in
accordance with the teachings of the present invention.

[0013]FIG. 4A depicts layers of an embodiment of a hybrid circuit
configured for use in a hearing aid including a substrate on which a flex
antenna is disposed, in accordance with the teachings of the present
invention.

[0014] FIG. 4B illustrates an embodiment for the flex antenna that is
configured as a layer in the hybrid circuit of FIG. 4A, in accordance
with the teachings of the present invention.

[0015] FIG. 4C depicts an embodiment for a flex antenna, in accordance
with the teachings of the present invention.

[0016] FIG. 5 illustrates an embodiment an antenna coupled to a circuit
within a hearing aid, in accordance with the teachings of the present
invention.

[0017]FIG. 6 shows a block diagram of an embodiment of a hybrid circuit
configured for use in a hearing aid, in accordance with the teachings of
the present invention.

[0018]FIG. 7 shows an embodiment of a capacitor network coupled to an
antenna configured within a hearing aid, in accordance with the teachings
of the present invention.

[0019] FIG. 8 shows a representation of an embodiment of a hearing aid in
which an antenna is driven on a middle turn by a drive circuit in the
hearing aid with two outside turns coupled to receiver circuits to
receive power from the middle turn, in accordance with the teachings of
the present invention.

[0020]FIG. 9 shows a representation of an embodiment of a hearing aid in
which a conductive line is situated in close proximity to an antenna
embedded in the hearing aid to measure power from the antenna, in
accordance with the teachings of the present invention.

[0021] FIGS. 10A-10D illustrate embodiments of antenna configurations in a
hearing aid, in accordance with the teachings of the present invention.

DETAILED DESCRIPTION

[0022] The following detailed description refers to the accompanying
drawings that form a part hereof and that show, by way of illustration,
specific details and embodiments in which the invention may be practiced.
These embodiments are described in sufficient detail to enable those
skilled in the art to practice and use the present invention. Other
embodiments may be utilized and structural, logical, and electrical
changes may be made without departing from the spirit and scope of the
present invention. The various embodiments disclosed herein are not
necessarily mutually exclusive, as embodiments can be combined with one
or more other embodiments to form new embodiments. The following detailed
description is, therefore, not to be taken in a limiting sense, and the
scope of the embodiments of the present invention is defined only by the
appended claims, along with the full scope of equivalents to which such
claims are entitled.

[0023] A hearing aid is a hearing device that generally amplifies or
processes sound to compensate for poor hearing and is typically worn by a
hearing impaired individual. In some instances, the hearing aid is a
hearing device that adjusts or modifies a frequency response to better
match the frequency dependent hearing characteristics of a hearing
impaired individual. Individuals may use hearing aids to receive audio
data, such as digital audio data and voice messages, which may not be
available otherwise for those seriously hearing impaired.

[0024] In an embodiment, a circuit includes an antenna configured in a
hybrid circuit for use in a hearing aid. In an embodiment, a circuit
includes metallic traces in a hybrid circuit configured for use as an
antenna in a hearing aid and contacts in the hybrid circuit to connect
the metallic traces to electronic devices in the hybrid circuit. Such an
antenna may be visualized as being embedded in the hybrid like layers of
a sandwich.

[0025] In general, a hybrid circuit is a collection of electronic
components and one or more substrates bonded together, where the
electronic components include one or more semiconductor circuits. In some
cases, the elements of the hybrid circuit are seamlessly bonded together.
In an embodiment, a hybrid circuit configured for use in a hearing aid
includes one or more ceramic substrates. In an embodiment, a hybrid
circuit configured for use in a hearing aid has a substrate on which an
antenna is disposed, where the substrate has a dielectric constant
ranging from about 3 to about 10. In various embodiments, the substrate
may have a dielectric constant less than 3 or a dielectric constant
greater than 10.

[0026] FIG. 1 depicts an embodiment of a hearing aid 105 having an antenna
for wireless communication with a device 115 exterior to the hearing aid.
Exterior device 115 includes an antenna 125 for communicating information
with hearing aid 105. In an embodiment, hearing aid 105 includes an
antenna having a working distance 135 ranging from about 2 meters to
about 3 meters. In an embodiment, hearing aid 105 includes an antenna
having working distance 135 ranging to about 10 meters. In an embodiment,
hearing aid 105 includes an antenna that operates at about -10 dBm of
input power. In an embodiment, hearing aid 105 includes an antenna
operating at a carrier frequency ranging from about 400 MHz to about 3000
MHz. In an embodiment, hearing aid 105 includes an antenna operating at a
carrier frequency of about 916 MHz. In an embodiment, hearing aid 105
includes an antenna operating at a carrier frequency of about 916 MHz
with a working distance ranging from about 2 meters to about 3 meters for
an input power of about -10 dBm.

[0027] FIG. 2A shows an overview of an embodiment of an antenna circuit on
a substrate 205 for inclusion in a hybrid circuit configured for use in a
hearing aid. The antenna of FIG. 2A includes a metallic trace 215 having
a number of turns. A turn is a traversal along a path that can be
projected on a plane such that the traversal is substantially around the
supporting substrate of the antenna. In an embodiment, metallic trace 215
has two to three turns on one layer. In an embodiment, metallic trace 215
has two and one half turns on one layer. Various embodiments for an
antenna may use any number of integral turns or partial turns. Contacts
225 and 235 provide electrical coupling to electronic devices of the
hybrid circuit. Contacts 225 and 235 may be configured as a plated
through-hole or via connecting metallic trace 215 on one layer of
substrate 205 to various electronic components of the hybrid circuit on
another layer or another substrate. As illustrated in FIG. 2A, an
embodiment for an antenna includes metallic traces that form a planar
coil design with a helical coil component. The helical coil component is
provided by a number of turns that advance a finite distance inward as
the number of turns increase. This configuration of turns generates a
planar spiral shape providing the antenna with an elliptical
polarization. Having elliptical polarization characteristics decreases
the intensity of the nulls in the antenna pattern, allowing reception of
signals close to the antenna null.

[0028]FIG. 2B shows an overview of another embodiment of an antenna
circuit on a substrate 210 for inclusion in a hybrid circuit configured
for use in a hearing aid. The antenna of FIG. 2B includes a metallic
trace having a layer of turns 220, a layer of turns 230, and a layer of
turns 240. In an embodiment, layer of turns 220 and layer of turns 240
are on one side of substrate 210 and layer of turns 230 is on the
opposite side of substrate 210 with a plated through-hole or via 250
connecting layer of turns 240 to layer of turns 230. Additional vias 260,
270, and 280 allow the antenna to be coupled to electronic components of
the hybrid circuit. Alternatively, each layer of turns 220, 230, and 240
are on different layers of substrate 210 and are connected to form a
single antenna by vias 250 and 270 with vias 260 and 280 connecting the
antenna to one or more electronic devices in the hybrid circuit. In an
embodiment, the metallic traces of the antenna have a loop configuration
having two ends, each of the two ends to couple to an electronic circuit
in the hybrid circuit. As illustrated in FIG. 2B, an embodiment for an
antenna includes metallic traces that form a planar coil design with a
helical coil component. The helical coil component is provided by a
number of turns that advance a finite distance as the number of layer of
turns advance. This configuration of turns generates a spiral shape
providing the antenna with an elliptical polarization. Having elliptical
polarization characteristics decreases the intensity of the nulls in the
antenna pattern, allowing reception of signals close to the antenna null.

[0029] In an embodiment as shown in FIG. 2A or 2B, the metal traces have a
total length of about 1.778 inches, a thickness of about 0.003 inches,
and a DC resistance of about 0.56 ohms. In an embodiment, an antenna in
the configuration of FIG. 2A has an outline size of about 0.212 inches by
0.126 inches by 0.003 inches. In an embodiment, an antenna in the
configuration of FIG. 2B includes three layers of turns of a coil having
a total thickness of 0.003 inches.

[0030] In an embodiment, the metallic traces of the antenna in a hybrid
circuit include a number of turns of a coil on the hybrid circuit. The
number of turns of the coil may be on one layer or on several layers in
the hybrid circuit. In an embodiment, losses for the antenna are
minimized using short trace lengths and a wider trace. Thicker traces may
be used to hold down inductance. In an embodiment, inductance is held
down to less than 14 nanohenrys for a self resonant frequency of an
antenna tuned to about 1.5 GHz. In an embodiment, the metallic traces
have a width and a combined length to provide a selected operating
distance for a selected input power. In an embodiment, the metallic
traces have a width and a combined length to provide a operating distance
ranging from about 2 meters to about 3 meters for an input power ranging
from about -10 dBm to about -20 dBm. In an embodiment, the traces are
silver traces. In another embodiment, the traces are silver and/or copper
traces. In another embodiment, the traces are gold traces. The traces may
be an appropriate conductive material selected for a given application.
As can be understood by those skilled in the art upon reading and
studying this disclosure, other metallic materials can be used as well as
varying number of layers of turns and varying layers in the hybrid
circuit on which the metallic traces are disposed.

[0031] Embodiments for antennas in a hearing aid such as those of FIGS. 2A
and 2B may be configured with other electronic devices for control of
wireless transmission of data to a hearing aid. In an embodiment, a
capacitor is coupled in parallel to the metallic traces of an antenna
such as the antenna shown in FIGS. 2A or 2B. In an embodiment, a
capacitor coupled in parallel to the metallic traces of the antenna is
part of a match filter. In an embodiment, the antenna is configured to
operate with a carrier frequency ranging from about 400 MHz to about 3000
MHz. In an embodiment, the metallic traces of the antenna are coupled to
a match circuit. The match circuit may be realized using different
approaches including but not limited to using a transformer, a balun, a
LC (inductive/capacitive) match circuit, a shunt capacitor, and/or a
shunt capacitor and a series capacitor. In an embodiment, an antenna is
configured with a balun in a hybrid circuit in the hearing aid. The balun
provides a balanced transmission line coupled to an unbalanced
transmission line.

[0032] Substrate 205 of FIG. 2A and substrate 210 of FIG. 2B include a
dielectric insulating material between the traces forming a planar coil
and a coil, respectively, as an antenna. The properties of the material
in which the antenna is formed determine the velocity of the radiation in
the material as well as the portion radiated from the antenna. The
dielectric insulating material is chosen to reduce the length of the
antenna in the hybrid circuit to be used in a hearing aid. In an
embodiment, a substrate for an antenna in a hearing aid is a polyimide
having a permittivity of about 3.9 providing the dielectric material
between the turns of the antenna. In an embodiment, a substrate for an
antenna in a hearing aid is a quartz substrate. In an embodiment, a
substrate for an antenna in a hearing aid is a ceramic substrate. In an
embodiment, a substrate for an antenna in a hearing aid is an alumina
substrate. In an embodiment, dielectric material in which the antenna is
embedded is a low temperature cofired ceramic (LTCC). In an embodiment,
dielectric material in which the antenna is embedded has a dielectric
constant ranging from about 3 to about 10. In an embodiment, a substrate
is selected from insulating materials such that the total length of an
antenna in a hybrid circuit for a hearing aid is less than approximately
0.2 inches.

[0033] FIG. 3A depicts an embodiment of a hybrid circuit 300 configured
for use in a hearing aid including a substrate 310 containing a planar
antenna. Various embodiments configured as similar to that shown in FIG.
2A or 2B may be used with an antenna layer 310 or 370. In an embodiment,
the antenna may include two or three turns in a single plane. In an
embodiment, the antenna may include two or three loops in two or three
separate planes. In an embodiment, the antenna may include any number of
fractional turns. In an embodiment, the antenna may include any number of
fractional turns between zero turns and three turns.

[0034] Hybrid circuit 300 includes several layers in addition to substrate
310 containing the antenna circuit. Hybrid circuit 300 includes a
foundation substrate 320, hearing aid processing layer 330, device layer
340 containing memory devices, and a layer having a radio frequency (RF)
chip 350 and crystal 360. Crystal 360 may be shifted to another location
in hybrid circuit 300 and replaced with a surface acoustic wave (SAW)
device. The SAW device, such as a SAW filter, may be used to screen or
filter out noise in frequencies that are close to the wireless operating
frequency.

[0035] Hearing aid processing layer 330 and device layer 340 provide the
electronics for signal processing, memory storage, and sound
amplification for the hearing aid. In an embodiment, the amplifier and
other electronics for a hearing may be housed in a hybrid circuit using
additional layers or using less layers depending on the design of the
hybrid circuit for a given hearing aid application. In an embodiment,
electronic devices may be formed in the substrate containing the antenna
circuit. The electronic devices may include one or more application
specific integrated circuits (ASICs) designed to include a matching
circuit to couple to the antenna or antenna circuit. The layers of hybrid
circuit 300 are bonded together or held together such that contacts of
antenna layer 310 can be coupled directly to contacts for other
electronic devices in hybrid circuit 300.

[0036] Hybrid circuit 300 provides a compact layout for application in a
hearing aid. In an embodiment, hybrid circuit 300 has a thickness 308 of
approximately 0.089 inches, a width 304 of about 0.100 inches, and a
length 306 of approximately 0.201 inches. In an embodiment, hybrid
circuit 300 has a thickness 308 less than approximately 0.100 inches, a
width 304 of about 0.126 inches, and a length 306 of approximately 0.212
inches. In an embodiment, antenna layer 310 is a polyimide substrate
having metallic traces configured as the antenna with a total length of
about 1.778 inches and a DC resistance of about 0.56 ohms. The metallic
traces may include silver traces, silver and copper traces, and/or copper
traces. In an embodiment, antenna layer 310 is a polyimide substrate
having metallic traces configured as the antenna, where the antenna layer
310 has a thickness of about 0.003 inches and the antenna has an outline
size, as laid around substrate 310 of approximately 0.212 inches by 0.126
inches by 0.003 inches. The antenna is shaped to provide a working
distance of about 2 to 3 meters at an input power ranging from about -10
dBm to about -20 dBm. A capacitor with an area of approximately 0.020
inches by 0.010 inches and a capacitance of about 5.2 pF is coupled to
the two ends of the antenna to balance or match the antenna. The
capacitor can be located on substrate 310 or on one of the other layers
of hybrid circuit 300.

[0037] An antenna in a hybrid circuit exhibits a complex impedance to the
electronics to which it is coupled. For proper operation, the antenna is
coupled to a matching circuit to provide impedance matching to the
antenna circuit. In an embodiment, the matching circuit is adapted to the
complex conjugate of the antenna complex impedance. The matching circuit
may be a matching filter, also referred to as a match filter. A match
filter can include several electronic components or a single capacitor
depending on the application. In an embodiment, the antenna is coupled to
a match filter consisting of a capacitor with an area of approximately
0.020 inches by 0.010 inches and a capacitance of about 5.2 pF. In other
embodiments, a match filter may include one or more inductors and/or
capacitors. The physical and electrical characteristics of the components
selected for the match filter depend on the complex impedance provided by
the design of the antenna. The length, width, thickness, and material
composition for the components of the antenna and match filter are
selected to match the complex impedance of the antenna. In an embodiment,
the length, width, thickness, and material composition for the components
of an antenna are selected for a circuit having metallic traces in a
hybrid circuit configured for use as an antenna in a CIC hearing aid.

[0038] FIG. 3B depicts a view of the embodiment of layers of hybrid
circuit 300 configured for use in a hearing aid shown in FIG. 3A
illustrating the planar antenna on a substrate in the hybrid circuit.
FIG. 3B demonstrates that the antenna configured integral to a hybrid
circuit for a hearing aid can be essentially directly coupled to
electronic devices and circuitry of the hearing aid with the bonding or
bringing together of the layers of hybrid circuit 300. In an embodiment,
metallic traces 312 are in substrate 310 in a single layer, and hence do
not protrude as a separate layer above the surface of substrate 310.
Alternatively, metallic traces 312 may protrude above the surface of
substrate 310 with appropriate insulation to avoid unwanted electrical
coupling. Metallic traces 312 have ends that can connect to electronic
devices on layers above and below antenna layer 310, respectively, as
well as electronic devices on layer 310. Alternatively, an antenna for
hybrid circuit 300 includes metallic traces 312 and metallic traces 314
in different layers of substrate 310, which do not protrude as separate
layers above or below the surfaces of substrate 310. Alternatively,
metallic traces 312 and metallic traces 314 may protrude above or below
the surfaces of substrate 310 with appropriate insulation to avoid
unwanted electrical coupling. Metallic traces 312 and 314 have ends that
can connect to electronic devices on layers above and below antenna layer
310, respectively, as well as electronic devices on layer 310. The
configuration of FIG. 3B eliminates the problems associated with
connecting an exterior antenna to components of a hearing aid.
Alternatively, hybrid circuit 300 can be configured with a housing such
that layers 320, 310, 330, 340, 350, and 360 are spaced apart with
electrical connections provided by wiring between the layers. Embodiments
for an antenna formed in the hybrid provides for a compact design that
can be implemented in the smallest type hearing aid as well as other
typical hearing aid types.

[0039]FIG. 4A depicts layers of an embodiment of a hybrid circuit 400
configured for use in a hearing aid including a substrate 410 on which a
flex antenna 420 is disposed. The layers of FIG. 4 may be bonded together
to provide a hybrid circuit configured similar to hybrid circuit 300 of
FIG. 3A. Hybrid circuit 400 includes a foundation layer 430 containing
electronic devices and circuitry for a hearing aid, and a layer having an
RF electronic chip 450 and crystal 460. Alternatively, foundation layer
430 can be configured in multiple layers similar to layers 320, 330, and
340 of FIG. 3A, B. Crystal 460 may be positioned at another location in
hybrid circuit 400 and replaced at the position in FIG. 4A with a SAW
device.

[0040] In an embodiment as illustrated in FIG. 4A, an antenna layer
including a flex antenna 420 disposed on substrate 410 provides an
embodiment for an antenna in a hybrid circuit for use in a hearing aid
different than the antenna layer 310 of hybrid circuit 300 illustrated in
FIG. 3B. Flex antenna 420 uses a flex circuit, which is a type of
circuitry that is bendable. The bendable characteristic is provided by
forming the circuit as thin conductive traces in a thin flexible medium
such as a plastic like material or other flexible dielectric material.
Flex antenna 420 includes flexible conductive traces 422 in a flexible
dielectric layer 424. In an embodiment, flex antenna 420 is disposed on
substrate 410 on a single plane or layer. In an embodiment, flex antenna
420 may have an extension 426 that extends out from substrate 410 into
the hearing aid shell (housing). In an alternative embodiment, flex
antenna 420 may have a portion 428 that curls around substrate 410 such
that it is disposed on two opposite sides of substrate 410. In an
embodiment, a hybrid circuit configured for use in a hearing aid includes
an antenna configured as a flex circuit having thin metallic traces in a
polyimide. Such a flex design may be realized with an antenna layer or
antenna layers of the order of about 0.003 inch thick. A flex design may
be realized with a thickness of about 0.006 inches. Such a flex design
may be realized with antenna layers of the order of about 0.004 inch
thick. A flex design may be realized with a thickness of about 0.007
inches as one or multiple layers.

[0041] FIG. 4B illustrates an embodiment for flex antenna 420 that is
configured as a single layer in hybrid circuit 400 of FIG. 4A. Flex
antenna 420 includes a conductive layer 422 in or on a dielectric layer
424. Conductive layer 422 may include a metallic layer formed as metallic
traces connected together or as one trace having a length equal to the
combined length of a conductive layer formed as connected metallic
traces. In an embodiment, conductive layer 422 is configured as metallic
traces having a rectangular loop configuration for use as an antenna. In
another embodiment, conductive layer 422 is configured as a metallic
trace having an approximate circular or elliptic loop configuration for
use as an antenna. The conductive layer 422 can be formed in other shapes
depending on the application in which an antenna is configured. In an
embodiment, the conductive layer 422 can be formed as multiple
rectangular loops, one inside another. In an embodiment, the conductive
layer 422 can be formed as two rectangular loops, one inside another. In
an embodiment, conductive layer 422 may be formed as two turns in flex
antenna 420. The metallic traces forming conductive layer 422 may be thin
layers of silver, copper, gold, or various combinations of these metals.
In various embodiments, appropriate conductive material for a given
antenna application forms conductive layer 422.

[0042] Dielectric layer 424 of flex antenna 420 is a flexible dielectric
material. It provides insulation for conductive layer 422 and
adaptability of flex antenna 420 to a substrate 410. Flex antenna 420 can
be disposed on substrate 410 or curled around substrate 410 as
illustrated in FIG. 4A. In an embodiment, dielectric layer 424 is a
polyimide material. In an embodiment for a flex antenna, as shown in FIG.
4C, a thin conductive layer 422 is formed in or on thin dielectric layer
424, where dielectric layer 424 has a width slightly larger than the
width of conductive layer 422 for configuration as an antenna. Such an
arrangement may be effectively wrapped around a substrate. An antenna
having such a configuration can be curled around substrate 410 of FIG. 4A
such that it has two layers of turns on one side of substrate 410 and one
layer of turns on the opposite side of substrate 410. In an embodiment,
substrate 410 is a quartz substrate. In an embodiment, substrate 410 is a
ceramic substrate. In an embodiment, substrate 410 is an alumina
substrate. In an embodiment, substrate 410 has a dielectric constant
ranging from about 3 to about 10. Disposing flex antenna 420 on substrate
410 and curling it around substrate 420 provides a antenna for hybrid
circuit 400 that is essentially planar with a helical component.

[0043] Hybrid circuit 400 and flex antenna 420 of FIG. 4A can be designed
with similar characteristics for operation and configuration as the
planar antenna of FIGS. 2A and 2B as used in FIG. 3A. In an embodiment,
hybrid circuit 400 has a thickness of approximately 0.089 inches, a width
of about 0.100 inches, and a length of approximately 0.201 inches. In an
embodiment, hybrid circuit 400 has a thickness less than approximately
0.100 inches, a width of about 0.126 inches, and a length of
approximately 0.212 inches. In an embodiment substrate 410 and flex
antenna 420 form an antenna layer configured with the antenna having a
total length of about 1.778 inches and a DC resistance of about 0.56
ohms. In an embodiment, flex antenna 420 has metallic traces 422 having a
thickness of about 0.003 inches, where flex antenna 420 has an outline
size, as laid out at around substrate 410, of approximately 0.212 inches
by 0.126 inches by 0.003 inches. The antenna is shaped to provide a
working distance of about 2 to 3 meters at an input power ranging from
about -10 dBm to about -20 dBm.

[0044] FIG. 5 depicts an embodiment of a helical antenna 510 coupled to a
hybrid circuit 520 in a hearing aid 500. Hybrid circuit 520 and helical
antenna 510 are arranged in a common housing for hearing aid 500. A wide
range for the number of turns may be used to configure helical antenna
510. Helical antenna 510 may be formed as conductive traces layered in a
dielectric medium. In an embodiment, the dielectric medium is alumina. In
another embodiment, the dielectric medium is quartz. In another
embodiment, the dielectric medium is a LTCC. In an embodiment, the
dielectric medium has a dielectric constant ranging from about 3 to about
10. In an embodiment, helical antenna 510 is configured as a 12 turn
helix. In an embodiment, helical antenna 510 is configured as a 20 turn
helix. The 20 turn helix may be configured to provide a 10 meter working
distance. Various embodiments may include any number of turns and are not
limited to 12 or 20 turns.

[0045] In an embodiment, helical antenna 510 may be coupled to the hybrid
circuit 520 by lead connections 512, 514. In an embodiment, each lead
connection 512, 514 has a length of about 3/8 inches. Other lengths for
lead connections 512, 514 may be implemented depending on the embodiment
for hearing aid 500. In an embodiment, hearing aid 500 having antenna 510
adapted to have working distance extending to about 10 meters can be
configured with additional circuitry including memory and controllers, or
processors, to allow hearing aid 500 to communicate with electronic
devices within the 10 meter working distance. Such a configuration allows
for reception of such signals as broadcast radio. In other embodiments,
hearing aid 500 has an internal antenna that allows hearing aid 500 to
communicate and/or receive signals from sources at various distances
depending on the application. Hearing aid 500 may be programmed for the
selective use of its wireless communication capabilities.

[0046]FIG. 6 shows a block diagram of an embodiment of a hybrid circuit
600 configured for use in a hearing aid. Hybrid circuit 600 includes an
antenna 610, a match filter 620, an RF drive circuit 630, a signal
processing unit 640, and an amplifier 650. Physically, hybrid circuit 600
can be realized as a single compact unit having an integrated antenna,
where the antenna can be configured as an embodiment of a substrate based
planar antenna, similar to that depicted in FIGS. 2A-2B, or as an
embodiment of a flex antenna, similar to that depicted in FIGS. 4A-4C. In
an embodiment, hybrid circuit 600 has leads to couple to antenna 610,
similar to that depicted in FIG. 5.

[0047] Match filter 620 provides for matching the complex impedance of the
antenna to the impedance of RF drive circuit 630. Signal processing unit
640 provides the electronic circuitry for processing received signals via
antenna 610 for wireless communication between a hearing aid in which
hybrid circuit 600 is configured and a source external to the hearing
aid. The source external to the hearing aid can be used to provide
information transferal for testing and programming of the hearing aid.
Signal processing unit 640 may also provide the processing of signals
representing sounds, whether received as acoustic signals or
electromagnetic signals. Signal processing unit 640 provides an output
that is increased by amplifier 650 to a level which allows sounds to be
audible to the hearing aid user. Amplifier 650 may be realized as an
integral part of signal processing unit 640. As can be appreciated by
those skilled in the art upon reading and studying this disclosure, the
elements of a hearing aid housed in a hybrid circuit that includes an
integrated antenna can be configured in various formats relative to each
other for operation of the hearing aid.

[0048] The elements of hybrid circuit 600 are implemented in the layers of
hybrid circuit 600 providing a compact circuit for a hearing aid. In an
embodiment, a hearing aid using a hybrid circuit shown as hybrid circuit
600 is a CIC hearing aid operating at a frequency of about 916 MHz for
wireless communication exterior to the hearing aid. In an embodiment, the
antenna for the CIC hearing aid operating at a frequency of about 916 MHz
is configured in a hybrid circuit as a substrate based planar antenna. In
another embodiment, the antenna for the CIC hearing aid operating at a
frequency of about 916 MHz is configured in a hybrid circuit as a flex
antenna. Various embodiments of hybrid circuit 600 may operate at
different frequencies covering a wide range of operating frequencies.

[0049]FIG. 7 shows an embodiment of a capacitor network 700 coupled to an
antenna 710 configured within a hearing aid. Capacitor network 700 allows
antenna 710 to be tuned by selectively coupling one or more capacitors
720-1, 720-2 . . . and/or 720-N to antenna 710. Capacitor network 700 may
be arranged as a capacitor ladder. Though shown as a network of parallel
capacitors, capacitor network 700 may be realized as a network of
capacitors in series. In various embodiments, series and/or parallel
capacitors may be included in a capacitor network. The selection of
capacitors may be controlled by enabling one or more selection units
725-1, 725-2 . . . and/or 725-N. Selection units 725-1, 725-2 . . . 725-N
may be transistors configured as transmission gates that electrically
couple its corresponding capacitor 720-1, 720-2 . . . 720-N to antenna
710 at the leads 730, 740. Selection units 725-1, 725-2 . . . 725-N be
configured as transmission gates using metal oxide semiconductor (MOS)
related technology, bipolar junction transistor (BJT) related technology,
or logic circuitry incorporating one or more microelectronic
technologies. The enabling signals, power circuitry, or other detailed
circuitry for selection units 725-1, 725-2 . . . 725-N are not shown to
focus on the application of the selection unit to couple one or more
capacitors 720-1, 720-2 . . . 720-N to antenna 710. Values for each of
the capacitors 720-1, 720-2 . . . 720-N can be chosen based on the
application in a particular hearing aid. In an embodiment, each capacitor
720-1, 720-2 . . . 720-N has a different capacitance value. In an
embodiment, each capacitor 720-1, 720-2 . . . 720-N has the same
capacitance value. Leads 730, 740 may be conductive traces on a substrate
of a hybrid circuit in the hearing aid.

[0050] Various embodiments include tuning series capacitors 750 to provide
for application in different parts of the world. The tuning capacitors
allow the antenna to be tuned between about 902 MHz and about 928 MHz.
This tuned frequency range may be used in the United States and Canada.
The tuning capacitors allow the antenna to be tuned between about 795 MHz
and about 820 MHz. This tuned frequency range may be used in China and
Korea. The tuning capacitors allow the antenna to be tuned to about 965
MHz or above. This tuned frequency range may be used in Taiwan. The
configuration of tuning capacitors is not limited to any particular
range, but may be adapted to a frequency range for the particular
application of an embodiment of an antenna in a hearing aid. In an
embodiment, tuning capacitors are configured in a parallel arrangement.

[0051] Various embodiments for antennas configured within the housing of
hearing aid may be realized. Embodiments also may include coupling the
antennas arranged in the hearing aid with matching circuit or matching
circuit elements. The matching circuit or element may be adapted to match
the complex conjugate of the complex impedance of the associated antenna.
The matching circuit may be realized using different approaches including
but not limited to using a transformer, a balun, a LC circuit match, a
shunt capacitor, or a shunt capacitor and a series capacitor. Various
embodiments for the matching circuit use inductances ranging from 10
nanohenrys to 40 nanohenrys and other embodiments use inductances ranging
from 30 to 40 nanohenrys. Various embodiments for the matching circuit
use capacitances of the order of 80 femtofarads. The shunt capacitor can
be realized as a capacitor network as discussed with respect to FIG. 7.
Providing a match circuit or matching circuit elements helps to reduce
loss associated with the antenna. In an embodiment, a -15 to -25 db
antenna or a -15 to -20 db antenna may be realized. Selecting the proper
element sizes for a match circuit may be conducted through a Smith chart
analysis and/or appropriate simulation techniques such as a finite
element analysis.

[0052] In an embodiment, an antenna for a hearing aid is adapted for
operation in the near field environment. Such an arrangement may occur
for antennas in a hearing aid used to communicate using a RF signal with
another hearing aid worn by the same person or with a programming device
that can be carried on the person wearing the hearing aid. In an
embodiment, the effects of a person's head are taken into consideration
in the design of the hearing aid to be incorporated in a hearing aid.

[0053] The head is essentially a non-magnetic material. However, the
electric field of an RF signal is attenuated through the head, and it is
attenuated through air. The level of attenuation through the head may be
a slightly greater than it is through the air. Antennas that utilize an
embodiment of this design attenuate signals less during passage through
high dielectric constant materials, such as the brain, muscle, and
tendon, than antennas not constructed under this principle. Body
dielectric constants and loss tangents are utilized more effectively in
this manner, opening up the passage of data through these materials with
this method.

[0054] With an antenna for a hearing aid located close to a person's head,
the quality factor, Q, which is related to the ratio of the frequency of
the carrier signal and the bandwidth of the signal, drops. In an
embodiment, the Q of an antenna is designed at a higher Q than desired
such that when operating in a hearing aid located on an individual, the
antenna has a lower Q, where the lower Q is within the desired operating
range. In an embodiment, an antenna is configured as embedded in a
dielectric material such that the configuration of the antenna including
the choice of dielectric material is designed to compensate for the
reduction of the antenna Q due to the proximity of the individual's head.
In an embodiment, the antenna configuration in the hearing aid is adapted
to compensate for the Q reduction provided by proximity of the user's
head with air used as the dielectric medium.

[0055] In an embodiment, the tuning of the antenna is accomplished in an
iterative fashion. The antenna of the hearing aid is tuned to a Q higher
than the desired operating Q. The antenna is tested in an operating
environment for the hearing aid. In an embodiment, the antenna is tested
in the operating environment with the hearing aid worn by a person. In an
embodiment, the antenna is tested in the operating environment with the
hearing aid having the antenna placed in a model of a person's head, in
which the model is configured with the electromagnetic characteristics of
a person's head. The antenna Q is further tuned either higher or lower
depending on the test results. With the antenna Q initially sent higher
than the operating Q, tuning may be realized by decreasing the Q in small
increments. The tuning of the antenna in an iterative bench tuning
process is a form of adaptive tuning or pre-emptive tuning. The antenna
is tuned outside the proximity of a person's head such that the antenna
is tuned wrong, that is, tuned so that is not correctly, fully tuned in
air. With interjection into the ear or in proximity to the ear depending
on the type of hearing aid, it is tuned to the desire operating
conditions. The hearing aid antenna may be tuned automatically either
while being worn by a person (or equivalently mounted in a model of a
person's head) or at a lab bench.

[0056] The testing of the antenna for the hearing aid can be accomplished
by transmitting a known test script to the hearing aid. The reception of
the test script is evaluated with respect to bit errors using a bit error
computation. If no bit errors occur, the antenna can be detuned until
there are bit errors followed by tuning it again. The tuning may be
realized through the adjustment in a matching circuit coupled to the
antenna. In a matching circuit using capacitors, the tuning includes the
change of capacitance value. In an embodiment, the capacitance can be
changed by selectively including capacitors using a capacitance network
similar to that shown in FIG. 7. Other embodiments may use other
mechanisms for tuning the antenna.

[0057] Testing of the antenna for the hearing aid may include testing of
power in the antenna. FIG. 8 shows a representation of an embodiment of a
hearing aid 800 in which the antenna is driven on a middle turn 822 by a
drive circuit 823 in hearing aid 800 with the two outside turns 824, 826
coupled to receiver circuit 825 to receive power from the middle turn. In
an embodiment, the middle turn and the two outside turns are connected as
part of a loop having high conductivity. By coupling power into one of
the outside turns, the power of the antenna using the middle turn can be
measured. The coupling may be an inductive coupling. The turns 822, 824,
and 826 and circuits 823 and 825 may be adapted to measure RF power from
turn 822. Drive circuit 823 and receiver circuit 825 may be configured as
a single circuit. An antenna configured as a middle turn may be coupled
to circuits in hearing aid 800 by use of contact vias, and outside turns
configured as receiver antennas may be coupled to circuits in hearing aid
800 by use of contact vias. With flex antennas, turns can be coupled to
circuits in the hearing aid by coupling the conductive material in the
flex antennas to contacts in the hybrid circuit, by coupling the
conductive material in the flex antennas directly to traces or
metallization paths in the hybrid circuit or by using coupling wires.

[0058] Hearing aid 800 may include circuitry to process and evaluate the
power measurement of the antenna based on signals from drive circuit 823
and receiver circuit 825. Alternatively, data from drive circuit 823 and
receiver circuit 825 may be provided to systems outside hearing aid 800
for evaluation. Communication of this data may be realized through
wireless communication or through wired communication.

[0059]FIG. 9 shows a representation of an embodiment of a hearing aid 900
in which a conductive line 905 is situated in close proximity to an
antenna 910 embedded in the hearing aid 900 to measure power from antenna
910. In an embodiment, conductive line 905 and antenna 910 are configured
at a distance 912 such that sufficient RF power is coupled from antenna
910 into line 905 to measure the power of antenna 910. In an embodiment,
distance 912 ranges from about 10 mils to about 20 mils. Conductive line
905 and antenna 910 may be adapted for inductively coupling power between
the two. Hearing aid 900 may include circuitry to process and evaluate
the power measured from conductive line 905. Alternatively, data obtained
from coupling power directly into conductive line 905 may be provided to
systems outside hearing aid 800 for evaluation. Communication of this
data may be realized through wireless communication or through wired
communication.

[0060] FIGS. 10A-10D illustrate embodiments of an antenna for a hearing
aid. FIG. 10A illustrates an antenna 1020 formed in substrate 1010. In an
embodiment, antenna 1020 is configured as a spiral. In an embodiment,
antenna 1020 is configured with approximately the same size as the hybrid
circuit (not shown) that can be mounted below or above antenna 1020 in a
hearing aid.

[0061]FIG. 10B illustrates antenna 1020 of FIG. 10A mounted on top of a
hybrid circuit 1030 in a "Top Hat" configuration. In an embodiment,
antenna 1020 is displaced from hybrid circuit 1030 by approximately 15
mils. Such a displacement is provided to eliminate or reduce proximity
effects of hybrid circuits.

[0062] In an embodiment, the size of antenna 1020 may be larger than that
of hybrid circuit 1030.

[0063] FIG. 10C illustrates an antenna displaced to one side from a hybrid
circuit. In an embodiment, antenna 1020 of FIG. 10A is employed with
hybrid circuit 1040. In an embodiment, hybrid circuit 1040 may be
constructed similar to hybrid circuit 1030 of FIG. 10B. Displacement to
the side of hybrid circuit 1040 provides space between hybrid circuit
1040 and antenna 1020 in a horizontal plane (loop plane). Such a
configuration also attenuates proximity effects of hybrid circuit 1040 on
hearing aid antenna 1020.

[0064] FIG. 10D illustrates an antenna 1022 on both sides of a hybrid
1050. In an embodiment, hybrid circuit 1050 may be constructed similar to
hybrid circuit 1030 of FIG. 10B. In an embodiment, antenna 1022 has two
turns 1024-1 on substrate 1010-1 and 1024-2 on substrate 1010-2, where
the two turns 1024-1, 1024-2 are on two different sides of hybrid 1050.
This configuration effectively adds a z-component to the transmitted wave
polarization from antenna 1020.

[0065] Embodiments may include various combinations of the configurations
shown in FIGS. 10A-10D for a hearing aid antenna. For example, such
combinations may include the relative size relationship of the antenna to
the hybrid as discussed with respect to FIG. 10A with the placement on
both sides of hybrid shown in FIG. 10D.

[0066] For placement of the various embodiments for hearing aid antennas
in the body, such as for CIC transceivers, design of the antenna
parameters may be performed to minimize proximity effects of the human
body. Such a design method may consider material effects of the ear
canal, brain, associated bone and connective tissue, and other parts of
the human body through which these signal inevitably pass. Such
consideration may be important for embodiments in which signals are
passed from one ear to the other ear. An antenna parameter that may be
considered includes the orientation of the antenna to avoid the proximity
effect of the human body, since human body effects are not limited to the
ear canal, but may include the volume of the entire body, which may
affect the radio signal. In embodiments for hearing aid, a transmitting
antenna to communicate with a hearing aid may be configured as a loop
antenna having placement in a pocket, attached to a belt, on a side
position such as a "holster" position, for example.

[0067] Mitigation of proximity effects of the body itself may be treated
by simulation of the human body tissue parameters placed to represent the
human body tissue as the tissue would be situated in a real environment.
In an embodiment, parameters may be given a particular placement to
simulate buttressing these tissue positions against antennas in various
orientations. Various embodiments include simulating these buttressing
positions to evaluate hearing aids. In an embodiment, buttressing
positions are simulated to evaluate BTE hearing aids, which rest against
the ear and side of the skull.

[0068] Antennas configured in hybrid circuits adapted for use in hearing
aids according to various embodiments provides a compact design for
incorporating a wireless link into small hearing aids. The integrated
structure of the antenna in the hybrid circuit allows for the elimination
of soldering a separate antenna to a hearing aid during manufacture.
Embodiments of the antenna can be utilized in completely-in-the-canal
hearing aids providing a wireless link over several meters at small input
power.

[0069] Although specific embodiments have been illustrated and described
herein, it will be appreciated by those of ordinary skill in the art that
any arrangement which is calculated to achieve the same purpose may be
substituted for the specific embodiment shown. This application is
intended to cover any adaptations or variations of embodiments of the
present invention. It is to be understood that the above description is
intended to be illustrative, and not restrictive and that the phraseology
or terminology employed herein is for the purpose of description and not
of limitation. Combinations of the above embodiments and other
embodiments will be apparent to those of skill in the art upon studying
the above description. The scope of the invention includes any other
applications in which embodiments of the above structures and fabrication
methods are used. The scope of the invention should be determined with
reference to the appended claims, along with the full scope of
equivalents to which such claims are entitled.

Patent applications by Beau Jay Polinske, Minneapolis, MN US

Patent applications by Starkey Laboratories, Inc.

Patent applications in class Remote control, wireless, or alarm

Patent applications in all subclasses Remote control, wireless, or alarm